package com.hmdp.utils;

import jakarta.annotation.Resource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.stereotype.Component;


import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {

    private static final long BEGIN_TIMESTAMP = 1640995200L;
    /**
     * 序列号的位数
     */
    private static final int COUNT_BITS = 32;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    public long nextId(String keyPrefix){
        //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;

        //2.生成序列号
        //2.1获取当前日期，精确到天
        //在redis以：分隔就会分层，方便统计，同时预防超出上线
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //用基本类型，后续还需要运算
        long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        //3.long拼接并返回
        //先向左移32位然后或运算
        return timestamp << COUNT_BITS | count;
    }

    public static void main(String[] args) {
        //获取这个时间点的秒数
        LocalDateTime time = LocalDateTime.of(2022, 1, 1, 0, 0, 0);
        long second = time.toEpochSecond(ZoneOffset.UTC);
        System.out.println("second = " +second);
    }
}
